1. Field of the Invention
This invention relates to systems for freezing food and, more particularly, to such systems employing refrigerated air to fast freeze foodstuffs such as hamburger patties and fish fillets.
2. Brief Description of the Prior Art
There are generally two preferred means of quickly freezing thin, flat food products like hamburger patties and fish fillets to minimize dehydration weight losses: cryogenic freezing in a straight-belt freezer or mechanical freezing in a spiral freezer. Cryogenic freezing has the advantage of very fast, low temperature freezing for minimal yield losses: typically 0.5% for raw hamburger patties); but the disadvantage of high operating costs through the use of expendable gases. Mechanical freezing uses cold air as the heat transfer mechanism for lower operating costs but sometimes at a slightly higher rate of dehydration, depending on product characteristics. Though modern mechanical freezing systems with advanced airflow design provide good freezing, they have not always completely bridged the gap that favors cryogenic freezing for minimizing dehydration losses.